Kinetic coefficient of steps at the Si(111) crystal-melt interface from molecular dynamics simulations

Abstract

Nonequilibrium molecular dynamics simulations are applied to the investigation of step-flow kinetics at crystal-melt interfaces of silicon, modeled with the Stillinger-Weber potential ͓Phys. Rev. B 31, 5262 ͑1985͔͒.Step kinetic coefficients are calculated from crystallization rates of interfaces that are vicinals of the faceted ͑111͒ orientation. These vicinal interfaces contain periodic arrays of bilayer steps, and they are observed to crystallize in a step-flow growth mode at undercoolings lower than 40 K. Kinetic coefficients for both ͓110͔ and ͓121͔ oriented steps are determined for several values of the average step separation, in the range of 7.7-62.4 Å. The values of the step kinetic coefficients are shown to be highly isotropic, and are found to increase with increasing step separation until they saturate at step separations larger than ϳ50 Å. The largest step kinetic coefficients are found to be in the range of 0.7-0.8 m / ͑sK͒, values that are more than five times larger than the kinetic coefficient for the rough ͑100͒ crystal-melt interface in the same system. The dependence of step mobility on step separation and the relatively large value of the step kinetic coefficient are discussed in terms of available theoretical models for crystal growth kinetics from the melt.

Anisotropy of crystal-melt interfacial free energy of silicon by simulation

“…Note also that SW potential has been used in a number of studies related to crystal-melt interface. 2,5,28 Nonetheless, it will be necessary to study the dependence of ␥ on the model potential 29 by employing several different potentials of silicon ͓e.g., Tersoff-89 ͑Ref. 30͔͒ and this task will be undertaken as a future work.…”

Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps

“…On a vicinal interface, steps advance one after another in step flow. Ledge growth and step flow processes have been observed in real time by high resolution TEM [97] and MD simulations [98]. If the impinging flux is too high or the terrace size is too large (a low nucleation rate of steps and/or high surface diffusivity), two dimensional islands are nucleated first, but subsequently these islands also expand by step flow growth.…”

Atomistic modeling of the thermophysical characteristics of silicon in the region of the semiconductor-metal phase transition

“…Изменение одного или нескольких из этих параметров влечет за собой изменение свойств твердого тела. Примером может служить синтез материалов кристаллической фазы с новыми свойствами путем контролируемого манипулирования их микроструктурой на атомарном уровне [9].…”